High and medium intensity searchlight



Nov. 19, 1929. P. R. BASSTT 1,735,947

HIGH AND MEDIUM INTENSITY SEARCHLIIGHT Filed Nov. 20, 1918l 3 Sheets-Sheet 1 IN VENTOR Nov. 19, 1929. P. R. BASSETT 1,735,947

HIGH AND MEDIUM INTENSITY SEARCHLIGHT Filed Nov. 20, 1918 5 Sheets-Sheet 2 Nov. 19, 1929. P. R. BASSI-:TT

HIGH AND MEDIUM INTENSITY SEARCHLIGHT Filed Nov. 20, 1918 5 Sheets-Sheel 7i JE.

l Patented Nov. 19, 1929 UNITED STATES PATENT A OFFICE PRESTON R. BASSETT, 0F BOOKLYN, NEW YORK, ASSIGNOR, BY MESNE ASSIGNMENTS,

` T0 SPERBY GYBOSCOPE COMPANY, ING., A CORPORATION OF NEW YORK lHIGH AND MEDIUM INTENSITY SEABCHLIGHT Application led November 26, v1 918. Serial No. 263,275.

This invention relates to arc lamps, especlally for use in connection with projectors,

and more particularly for use in searchlights of the drumless or open type. This application contains some of the substance disclosed in my co-.pending application, Serial No. 252,114 for improvements in drumless searchlights, filed August 30, 1918, and is as to `such substance a continuation of said application.

The principal objectof the invention is to provide a powerful searchlight, simple and compact in structureand capable of rapid and accurate manipulation and in which the lam will burn and otherwise function with a high degree of satisfaction without the necessity of beinglenclosed within the usual searchlight drum. j.

Another object is vto provide efficient but simple mechanism for strikingfthe are and feeding the electrodes and for rotating vat least one of said electrodes.

. A further object is to provide means whereby the relative positions of the arcing ends ofthe electrodes may be readj usted while the searchlight is in operation to compensate for defects occurring during such operation.

A still further object is to provide means for occulting the searchlight when the current is turned off and the electrode tips continue to glow, or even while the arc isstill burning, and for Ventilating the are under such condition. Y

Still another. object is to devise a method and means whereby the arcl llame vmay be stabilized and properly directed away from the are.

Referringto the drawings wherein I have 'shown what'I now consider to bev the preferred form of my invention: l z

Fig. 1 is an elevat1on of the lamp mechanism.

Fig.l 2 is a section'taken on line 2 -2 of Fig. 1, showing the light-proof and practically air-tight partition through which the positiveelectrode protrudes down into the arc cliamber.

Fig. 3 is a section thereofi taken on line 33=of Fig. 2.

Fig. 4 is a. view looking up from under-the mechanism as indicated by the arrow A, l

Fig. 1.

Fig. 5 is a section taken approximately on line 5 5 of Fig. 7 showing a centralizer for the negative electrode holder.

Fig. 6 is a' section taken on line 6-6 of Fig. 5.

Fig. 7 is a section in elevation of the lower half of the lamp mechanism, and a fragment of the mirror for projecting the beam; some of the manipulating parts being slightly displaced to show more clearly their structure l and function.

Fig. 8 isl a detail of a quick acting nut approximately on line 1 0-10, Fig. 1, of the relative positions of the electrodes and current conductors.

Fig. 11 is a detail of the positive electrode holder.

Figs. 12 and 13 are views of the electrode holders and current conducting units, showing the adaptability of the lamp to high andlow or medium intensity work, Fig. 12 showing the .arrangement used for high intensity, which is also shown in Fig. 7 and Fig. 13 showing theA arrangement used for low intensity. 1

The la p unit or lamp cartridge, as it is sometimes termed in military parlance, is shown at 1\i/n Fig. 1 and may fit into the middle of the projecting mirror indicated by dotted lines 2; a hole in the center of said mirror being provided for this purpose. The lower end ofthe lamp unit which contains most of the adjusting handles thus projects through to the back of the mirror, sothat the lamp may be entirely controlled from the back of the mirror while in operation.

The lamp unit is shown-as comprising a base portion 3, from which a plurahty of I rods or brackets reach upwardly to form their upper ends to a common member 5.

against lateral movementsvwith respect tothe mirror. l

To fiX the lamp against longitudinal movements within sleeve 7, I may employ a pin 11 in sleeve 7 pressed by a spring 12 into one of several holes 13 in the base portion 3 of the lamp; the several holes l'peimitting varyhold the nut closed over threaded rod 19. B

ing of the distance between the light source located in the end 14 of the positive electrode 15-or 15 and the projector 2, for varying the width of the searchlight beam. To remove the lamp from the projector, lthe knob 16 may be pulled outwardly to withdraw pin 11, and the lamp lifted out of sleeve 7.

The positive electrode 15 is shown as gripped by a holder 17 slidably mounted at 18 on a threaded rod 19 and at 20 on a guide rod 21. Attached toVV said holder is a split nut 22 (see also Fig. 8), having wings 23 and 24 thereon pivoted at 25. A spring 26 may be provided to normally spread the Wings and manually pressing the wings 23 and 24 together, the nut 22 becomes released from rod 19 and the electrode holder 17 may be' slid up and down rod 19 to any desired position. The wings are then released and further Inovement of the holder to effect the adjustment or feeding of the positive electrode isl accomplished by rotating handle'27 fixed on the lower end of rod 19. Means may also be provided whereby the rotation of rod 19 to feed the electrode will also effect the rotation of the electrode. This is shown in Fig. 11 where the sleeve portion 18 is provided with an internal projection 99 reaching into a slot 100-running lengthwise in threaded rod 19, so that while the sleeve may slide up and down said rod it will rotate when the rod is rotated the sleeve having a bearing 1at 101 in the holder 17 The electrode is contained within a sleeve 102 having an inner lining of insulation 103 for insulating the electrode from the lamp. 104 and is provided with a gear 105 meshing with a gear 106 on sleeve 18, so that rotation of sleeve 18 will cause a rotationof sleeve 102 with the electrode.

The electrode projecting downwardly from holder 17 may pass through light-proof partition 28 into the combustion chamber 29 and is preferably insulated from said partition. For this purpose I have shown the electrode as passing through a sleeve 30 separated from Sleeve 102 is rotatably mounted at 'said partition by insulation 31 and passing through an opening 32 in the partition. Also resting on said insulation 3 1 is a member 33, from which one or more electric conductors 34, 35 and .36 may project downwardly through insulation 31 and partition 28 without touching said partition, to a common member 37. An electric conductor 38 may be connected to member 37 or to one of the conductors as for instance, conduct-or 34 as shown at 39, and to a rod 40 (see also Fig. 7), which passes downwardly through tube 41 and through a hole 42 in the wall thereof to a binding post 43 to which the lead 44 is connected.

In Figs. 2 and 3, brushes 45 and 46 are shown attached to bars 47 and 48 connected by a link 49 at one of each of their ends and by a spring 50 at their other ends tending to pull said bars together for pressing said brushes inwardly through the sleeve portion 51 of member 33, against electrode 15. A conductor 74 attached to each of the brushes, and to member 33 as at 75 insures good electrical conta-ct between electrode 15 and said member 33.

In Fig. 7 the negative electrode 52 is shown supported in a holder 53 on the end of a rod 54 which rod is provided with rack gearing 55 and is slidable up and down through guides 56 and 57 on a rod 58. The bottom of rod 58 is integral with a cross arm 59 which is held y in c'place by a thumb nut 60 (see also Fig. 4),

adapted to hold said cross arm against a metallic plate 61. A spring 62 maybe prof vided between said arm and said plate 61 so that although the nut be loosened, a good electric contact will continue bet-Ween arm 59 and plate 61. Plate 61 is insulated from the base portion 3 of the lamp by means of insulation 62', and may be provided with a binding post 63 (see also Fig. 4) to which the feed line may be connected. The current will then pass from said binding post through plate 61, cross arm 59, rod 58, rod 54 to electrode 52'; springs 63 on rod 58, pressing against rod 54, being provided to insure good contact between both of said rods. j

A worm gear 64 on a rod 65 having bearings in guides 57 and 66 on rod 58 is shown engaging rack gearing 55, and may be actuated by turning knob 67 on rod 65 to move electrode 52 or 52 toward or away from electrode 15 .or 15. A spring 68 on rod 65 between guide 57 andcollar 69 may tend to hold worm 64 normally down against guide 57 as shown.

l To strike the arc, knob 67 may be pushed upwardly against the pressure of spring 68, causing worm 64 and rod 54 to rise and carry electrode 52 into contact with electrode 15". Knob 67 is then released, allowing spring 68 to draw the are. Subsequent adjusements of electrodev 52 will be made by the turning of K'knob 67.

This can ordinarily be corrected by a read- )justment of the relative positions of the electrodes. I have, therefore, devised means whereby said readjustment may readily be effected. To this end I have shown a cen-` tralizing member 70 for the electrode supporting rod 54, adapted to permit rocking of said rod. The portions 71 of said centraliz- -ing member 70 which engage sleeve 41 are preferably of non-conducting material. By loosening thumb nut 60 and moving knob 67 laterally, obviously a rocking effect of rods 54 and 58 will takeA place with member 70 as a pivot, and move the arcing end of the negative electrode with respect to that of the positive.

Referring now to the arc and its control, I have shown a chimney 72 opening at 73 into the arc chamber 29 for carrying off the fumes from the arc and to also create a draft which will cause the flame 74 (Fig. 7) to sweep to one side and out of the arc cham'- ber. In this connection I may also use the mutual repelling effect of electric currents traveling in opposite directions along parallel conductors. It is partly for this reason that I have shown the rods or conductors 34, 35, and 36 running substantially parallel with the electrodes 15 and 52. The current passing up through electrodes 52 and 15, enters member 33 through brushes 45 and 46, then passes down through rods 34, 35, and 36 and out thrgugh conductors` 38 and 40 to the return line. In highl. intensity arc lights, employing electrodes 1n which the positive contains a core of lightvemitting substance and the negative contains an arc sustaining core, that is a core from which the negative flame tends to emanate, the light is produced almost entirely from a small ball of flame contained Within the positive crater. The best results are obtained by causing the negative flame to maintain a sweeping contact with the burning end of the positive electrode; the tongue 120 of the negative flame sweeping by without touching the positive crater as shown in Fig. .12." A deflectionof the flame 74 is ef- 'fected by the use of oney conductor 34 as shownin Fig. 12. v

In the case of medium or low intensity arc lights, however, where plain carbon electrodes are used andthe light emanates from the white hot carbon itself, the negative flame is permitted to strike thepositiveelectrode, directly'. In thisy connection, it is desirable to maintain a steadying influence uponv the flame'so as to prevent it from wobbling and` constantly varyingv its relation with the positive electrode'. It is principally for this purpose that'the several conductors 34, 35, and

36 are placed around the flame. If these con-4 ductors are/arrangedfhowever, so as to hold the flame in a precisely central position, the flame, after striking will spread out and engage the said conductors and burn them off. The conductors are, therefore, positioned as shown in Fig. 10, this view being taken on line 10-1O of Fig. 1. The conductor 34 is shown on the side of the electrode 15 opposite the chimney 72, conductors 35 and 36 being placed equal distances from conductor 34 on opposite sides of electrode 15, and the electrode being slightly on the side toward conductor 34 of an imaginary line drawn through conductors 35 and 36. This relative positioning may, of course. be-varied as long as the resultant of their combined effect is in the desired direction. Thus while the effect of the conductors will be to steady the arc flame in a substantially central position, the resultant of their repelling effect will be toward a definite direction; preferably toward the chimney. After the flame has struck the positive electrode it will be prevented from wandering by the definite directing force of the current in the adjacent conductors.

In order to make the lampvadaptable to both high and lov@ intensity work, means, such as a switch, may be provided for placing one conductor 34, or the several conductorsl 34, 35, and 36, into the arc circuit. I prefer, however, to weld said several conductors to the common connecting-piece 37, so as to insure perfect distribution ofthe current flowing through them, to effect the correct influence upon the arc. I may, therefore, employ separate conducting units, one having the several conductors as in Figs. 1 and 13, and one having but one conductor as in Figs. 7 and 12. A change may be made by disconnecting conductor 38 at 39, lifting meinber 33 out of the lamp and substituting member 33 12. In this connection it will be noted that 4the brushes 45 and 45 as well as sleeves 30 and 30 through ywhich the electrodes protrude into the arc chamber are adapted to lit the electrodes 15 and 15 respectively.

The positive electrode holder 17 may be constructed to receive the larger electrode 15, while in order to adapt it to receive the smaller high-intensity electrodel any suitable reducing means, such as a sleeve 107, may be placed within the insulating member 103.

A `similar sleeve 108 may be provided for the negative electrode holder 53 for the electrode 52.

In order that the operator below or behind the lamp may be able to observe the arc, I may employ an optical device 75 having prisms or mirrors 76 and 77'to reflect the image of thearc upon the ground glass 78. Any other suitable device maybe employed for this purpose;`l

vat) 'patent' I have also provided means for occulting.

the lamp to prevent the emanation of light from the glowing electrodes when the current is turned oil, or even from the arc when it 5 is burning. For this purpose I may employ a shield j79 litting closely and slidably at its lower end 80 around tube 41 and adapted to be moved into the dotted line position 79. a light proof joint being provided at 81 where the upper edge of the occulter meets ,the lower edge 29%* of the walls of the arc chamber 29. To manipulate the occulter, I may employ a rod 82 havingia knob 83. Said rod is shown as passing through a sleeve 84 secured to the occulter at 85. A pair of vsprings 86 secured at 87 to said sleeve 84 are provided with lugs 88 projecting through sleeve 84 and' engaging rod 82 at 89. Rod 82' is in turn provided with a recess 90 into which said lugs are adapted to fit. To close `the occulter, rod 82 may be pulled down until said recess 90 lies adjacent lugs 88 and springs 86 press the lugs into the recess. The raising of the rod will now move the occulteLinto the dotted line po- .2'5 sition. The tightening of thumb nut 91 on a projection 92 on the base 3 of the lamp and through which rodv82 passes, will fasten the occulter in the closed position. When the occulter lis open as shown, instead of permit- 3o ting rod 82 lto project its full length below and outside of the lamp, it may be sliped up into the lamp in the position shown, by spreading springs 86 .and thus removing lugs 88 from recess 90. For the spreading of said springs 86 a tapering member 93 may beV provided slidable on rod 82. When lugs 88 are in recess 90 and the lower'ends of springs 86 consequently lie close to rod 82, the sliding of member 93 upwardly will obviously spread the said springs and lift said lugs out of engagement with the rod. f

When the occulter is closed, it forms a portion of a complete enclosure or container for the arc, so that the opening ot the vocculter consists in the removal of a part of the container to an inoperable position. Y

Across the lower opening of tubev 41 I have shown a late 94 which may be fastened' to arm 59. T e purpose ofsaid plate is` to prevent light from leaking out through said tube 41 when the occulter isclosed.l The plate may be slightly lower than base portion 3 as yshown at 95, to permit air to enter to feed the arc.' Also, to prevent light from escapingthrough thel chimney 72, I may place a cap 96 over the top of the chimney, andV bailles 7 within requiring the escaping gases to take aA course'represented by lines98. l

In aciordancewith the provisionsfof the sctatutes, I have herein described the principle of o eration of my invention, to-

gether with .t e apparatus, which. I now considerto represent the best embodiment thereof, but I desire to have itvunderstood 85 that the apparatus shown is only illustrative and that theinvention can be carried out by other means. Also, while it is designed totuse the various features and elements in the combination and relation described, some -of these may be altered and others omitted without interfering with the more general results outlined, and the invention extends to such use.

Having described my invention what I claim and desire to secure by Letters Patent is:

1. In an arc lamp, a pairfof holders adapted to support electrodes for producingan are, a light-proof enclosure for the arc, an air in- 'y take and an exhaust connected with said enclosure and a current carrying conductor positioned on,tl1e side of the arc opposite said exhaust. l

2. In a searehlight, a projector, holders for supporting electrodes for producing an arc, a light-proof container for the arc, said container being provided with an air intake and an exhaust, an electric conductor on the side of the arc positioned opposite said exhaust and connected to carry a current in a direction opposite to the direction of the flow across the arc and means for opening said container.

3. In a searchlight, a projector, holders for supporting electrodes for producing an arc, al

v light-proof container for the arc, said container being provided with an air intake and an exhaust, a plurality of electric conductors adjacent the arcposition and connected to carryl a current in substantially the opposite 100 direction to that in which-the current passes i across the arc, said conductors being so positioned' that the combined repelling force caused upon the arc will be toward said exhaust, and means for opening said container.

4. In a Searchlight, a parabolic refiector having anvopening through the centerithereof, an arc lamp unit supported within said.

' opening, said unit including electrode hold-- ers, means for. feeding the electrodes toward 1F10 eachlother, a shield for partially enclosing an arc, means for occulting the arc, said feeding means and said occulting means being controllable from the back of said reflector,

and means for observing the arc ltroni the'r `115v back ot said reflector. 4 ,K j

5. I-n an arclamp, meians'flor gripping-an electrode, a common threadedl means for feeding saidvgripping,meanslongitudinally, and '2 for rotating' the same, and means for releasl o 'ing said` gripping meansfrom' the feed. conj trolb ysaid, threaded means whereby the f gripping ineansand the eleyctroile'may'l be -fqu'ickly adjusted. j A l y r 6. In an arc lamp, meansrforv gripping an electrode, a threaded rod, a split nut ons'aid rod and supporting said means, means for rotating said gripping means in response to the rotation of said rod, and means whereby said ,o prising a forward stationary sleeve adjacent nut may be opened to permit movement of the electrode without rotating the same.

7 In a searchlight, a projector, a pair of spaced hollow members having openings on their sides nearest each other,'holders adapted to support a pair of electrodes between said members, a sleeve-like member telescopically engaging one of said hollow members, means for moving said sleeve member into engagement with the other of said hollow members for enclosing the opening between said hollowJnembers, an air inlet and an exhaust port connected with said members, and means for deflecting the arc produced by the electrodes toward said exhaust port.

8. In an arc lamp mechanism, a support, a carriage. slidably but non-rotatably mounted on said support, electrode gripplng means rotatably but non-slidably mounted on said carriage, a threaded shaft rotatably but nonslidably, mounted on said supportand adapted to engage coacting threads on said carriage, and means including a gear having a spline and splineway connection with said shaft for rotating said gripping means on rotation of said shaft.

9. In an arc lamp, an electrode holder comprising a forward stationary sleeve adjacent the arc, a rearward slidable carriage, a rotatable member thereon adapted to be clamped to the electrode, a shaft threaded in said carriage, means for rotating said shaft,'a gear, and means whereby said gear is slidably but non-rotatably secured to said shaft `for rotating said member.

10." In an arc lamp,` the combination with an electrode holder and a support of a second on said second rod meshing with said gearing,v

electrode holder, a rod supporting the same, said rod beiny slidable longitudinally in said support and eing provided with rack gearing, a second rod rotatably and slidably mounted in said support, a worm secured and resilient means tending to hold said sec`I ond rod against ,sliding movement in said l support.'

d 11. In an arm lamp, a pair of electrode holders adapted to be adjusted to receive electrodes of different cross sections, and means for securing interchangeable conductors to the lamp adjacent and substantially parallel Yto the electrodes. f

- 12. In an arc lamp mechanism, asupport, a carriage slidably but non-rotatably mounted on said'support, electrodeegripping means rotatablfy butA non-slidably mounted on said c ari vriage, a threaded `shaft rotatably but nonslidably mounted on said support and adapted to engage co-actilng threads on saidcarriage, and means including a gear having a spline the arc, a rearward slidable carriage, a rotatable member thereon, means whereby said member may be clamped to the electrode, a threaded shaft extending between said sleeve and carriage, and threaded in said carriage, means for rotating said shaft and a gear slidably but non-rotatably secured to said shaft for rotating said member.

14. In an arc lamp, means for gripping an electrode, a common threaded means for feeding said gripping means longitudinally and for rotating the same, and means for releasing said gripping means from the feed control of said threaded means whereby the grippin means and the electrode may be quickly a j usted while the electrode is rotating.

15. An open type searchlight comprising an arc lamp including the regulating mechanism therefor, a tubular occulter slidably mounted on said lamp, a reflector having a central opening, a mounting for the reflector and means on the mounting concentric with said opening for supporting the arc lamp with its regulating mechanism and occulter.

16. An open type searchlight comprising an arc lamp including the regulating mechanism therefor, occulting means carried by said lamp, a reflector having a central opening,

a mounting for the reflector, and means on the mounting concentric with said opemng for supporting the arc lamp with its regulating signature.

' PRESTON R. BASSETT.

and splineway connection with said shaft for rotating-said 'grippingmeans on rdtationof said shaft. Y i

13. In an arc lamp, an electrode holder com- 

